Battery chargers enabling the comparatively rapid charge of temperature sensitive batteries, such as nickel-cadmium batteries, are well known in the art. Many of such chargers have utilized various arrangements for preventing damage to the battery during the charging operation, but none of the battery chargers properly regardable as fast chargers are known to have taken into consideration all of the various physical changes that such batteries undergo when they are being rapidly charged, in order to prevent damage.
Although many prior art chargers have sensed both the battery voltage and battery temperature, none have been known to generate a reference voltage which varies in a similar fashion to the theoretical battery voltage, which reference voltage is then used to bring about a particularly effective charging rate. Although prior art devices are known that control average charging current, such have typically utilized a waveform in the shape of a rectangular wave, with very abrupt changes in battery current. This is of course to be contrasted with the highly advantageous sawtooth waveform generated and utilized in accordance with my invention.